[R] different colors for two wireframe spheres

[David Schellenberger Costa]

Dear List,

I have the code below adapted from the lattice-package examples to draw two spheres. I would now like to give
both different surface colors, e.g. one red and one blue. 

 ## 3-D surface parametrized on a 2-D grid
					 
			 n <- 10
			
			 tx <- matrix(seq(-pi, pi, length.out = 2*n), 2*n, n)
			 ty <- matrix(seq(-pi, pi, length.out = n) / 2, 2*n, n, byrow = T)
			 xx <- cos(tx) * cos(ty)
			 yy <- sin(tx) * cos(ty)
			 zz <- sin(ty)
			 zzz <- zz
			 
			 bxx <- xx+5 
			 byy <- yy+5
			 bzzz <- zzz+5
			 
			 xx=rbind(xx,rep(NA,n),bxx)
			 yy=rbind(yy,rep(NA,n),byy)
			 zzz=rbind(zzz,rep(NA,n),bzzz)
			 gr<-rbind(matrix(1,n,2*n),rep(NA,n),matrix(2,n,2*n))
			
			 wireframe(zzz ~ xx + yy, groups=gr,col.groups=c("red","blue"))

I tried various parameters as col.groups, col.regions but I have the impression that the "groups" argument in the wireframe command can only be used when supplying a data argument, which does not allow to plot the spheres as far as I tried. Is there a solution for this?

Cheers

David Schellenberger